Tennis royalty is Down Under to try to capture the first major crown of the year, but two players should rise above all others in the opening test of 2013, which starts on Monday, writes Tym Glaser.

The king of the Australian Open has returned to defend his title and, on face value, it's hard to see him not leaving his southern dominion with the Grand crown still upon his head.

Novak Djokovic of Serbia returns the ball during a practice session. [Photo/Agencies]

Former court jester, Novak Djokovic, faces a dangerous set of usurpers in the likes the all-time greatest male player, Roger Federer, and rising British star Andy Murray, who became a full member of men's tennis' four musketeers with breakthrough victories at the London Olympics and the US Open last year.

However, the fourth musketeer, whom we shall call Rafael d'Artagnan, blighted by injury and illness since Wimbledon last year, has opted not to head for glory at Melbourne Park and instead rest his ailing body for greater challenges throughout the 2013 season; although, there is a growing suspicion that the Spanish Bull's high-octane style of play is finally catching up with his body.

The are a number of pretenders to the Australian men's throne, the foremost of whom is Argentine Juan Martin Del Potro, who also had injury struggles last season. Also in the reckoning are big-serving Canadian Milos Raonic, who is due for a breakout season on the circuit, and the consistent David Ferrer, who will lead the Spanish armada which often struggles in the fickle southern hemisphere climes.

However, the two most likely to run away with the Serb's crown are 17-time Grand Slam winner Federer and the ever-improving Murray. Fortunately for the 'Djoker', they will have to duel in the semis to reach him, while his path looks alarmingly smooth with no Nadal to bother him in the top half of the draw.

World No 3 Serena Williams of the US remains the most feared women's player on the WTA circuit.  [Photo/Agencies]

If Djokovic looks a safe bet to win Aussie Open title No 4, Serena Williams, in the form of her life - and that's saying something, is unbackable and set to don the crown she has worn five times before. She won two more Grand Slam titles last season (Wimbledon and US Open), crushed all her foes in straight sets at the year-end WTA Championships, had a break, and then walloped the field at her Open warm-up tournament in Queensland.

At 31, she's not getting any younger, but nobody is consistently rising up to challenge her seat at the top of the women's tree and if she carries on in such a vein for the next two or three years, she will be inarguably the greatest female player the game has seen.

In fact, she may already be.

Her 15 Grand Slam titles are only behind Martina Navratilova and Chris Evert (18 apiece), Steffi Graf (22) and Margaret Court (24) among players of the modern era. Not wishing to downplay Court's greatness, but 11 of her titles came at the Aussie's home Open when many of the world's best were reluctant to make the long trek to the antipodes.

Now the game's best head to Australia in droves and maybe Russia's Maria Sharapova could provide a stern test in a potential final showdown.

Defending champion and No 1 seed Victoria Azarenka, of Belarus, could be a tricky foe in the semis, as could in-form Pole Agnieszka Radwanska, who is seeded to meet Sharapova in the semis, but if all the ladies bring their A games, there will only be one winner.

The Australian Open is the toughest of the four Slams to predict as you don't know exactly where all the players are with their games so early in the season and the weather can be brutally hot (although predictions are for a pretty comfortable first week, at least, in Melbourne).

No matter the opposition or the weather, expect Djokovic and Serena to win their games for the thrones.

China's Li Na has come closer to winning the Australian Open than any Asian and, in the midst of her usual run of good form to start the season, will be confident she can take the final step up at Melbourne Park this year. [Photo/Agencies]

In photos:

Players get Aussie treats ahead of Australian Open

Title holders start Australian Open defence